Application of a Distributed Algorithm in Wireless Networks

In this paper, we propose a new mechanism to select the cells and the wireless technologies for layer-encoded video multicasting in the heterogeneous wireless networks. Different from the previous mechanisms, each mobile host in our mechanism can select a different cell with a different wireless technology to subscribe each layer of a video stream, and each cell can deliver only a subset of layers of the video stream to reduce the bandwidth consumption. We formulate the Cell and Technology Selection Problem (CTSP) to multicast each layer of a vid-eo stream as an optimization problem. We use Integer Linear Programming to model the problem and show that the problem is NP-hard. To solve the problem, we propose a distributed algorithm based on Lagrangin relaxation and a protocol based on the proposed algorithm.The SECOAS project is exploring the use of wireless sensor networks as an alternative to traditional oceanographic data acquisition methods for monitoring harsh and inaccessible environment. In this paper we present our approach to the development of the distributed applications that runs on the sensor nodes to give collaborative processing, with an emphasis on creating clusters of nodes with similar spatial attributes. The use of distributed algorithms fulfil the requirements of a self-organising, self-managing and self-optimising network, and provide the extra benefit of the simple addition, removal and alteration of functionality. Our approach is illustrated with a description of clustering and auto-positioning algorithms to show self-organisation and emergence of global order by applying simple local rules. Dissemination of operational parameters between algorithms are realised by the gossip protocol. The distributed algorithms are supported by the light-weight operating system in SECOAS which is called kOS. The way this platform supports the algorithms as well as collaboration between them is discussed in the paper.